Probing the EOS of neutron stars with heavy ion collisions

The nuclear equation of state (EoS) underpins our knowledge of how nucleons assemble themselves from finite nuclei to neutron stars. The nuclear and astrophysical communities are taking a multifaceted approach to studying this important relation: from ground and space-based observations of neutron stars and their mergers to laboratory measurements of nuclear reactions and electron scattering. The past few years in particular have seen a number of high-profile measurements on the equation of state from these approaches. With the next generation accelerator facilities coming online, the nuclear science community is poised to further improve our understanding of the nature of neutron-rich nuclear matter with terrestrial measurements. The Facility for Rare Isotope Beams (FRIB) will provide a unique opportunity to study the nuclear equation of state at both super-saturation density, as well as large isospin asymmetry. This is particularly true as we look forward to the upgrade to 400 MeV/u.

I will present some recent experimental results from heavy-ion collisions from the National Superconducting Cyclotron Laboratory, highlighting the kinds of measurements that can be made in the early days of the FRIB Laboratory. I will then discuss the future experimental efforts that will be undertaken to constrain the EoS at high density, including the mid- and long-term plans with Time Projection Chambers and the High Rigidity Spectrometer.